How to Prune New Zealand bur?
Cut back old flower stems after flowering

New Zealand bur · Acaena affinis
Also known as: New Zealand burr
This plant is listed on Schedule 9 of the UK Wildlife & Countryside Act (Northern Ireland) as an invasive non-native species. Although not banned from sale, it is an offence to plant or cause these to grow in the wild IN NORTHERN IRELAND Gardeners possessing them should undertake measures to control them. See RHS advice on invasive non-native species for further information
Cut back old flower stems after flowering